Method of and means for heating liquids



I 1927, l 622569 March 29 F.. w. BIRTCH METHOD OF AND MEANS FOR HEATING LIQUIDS Filed Feb. 5, 1925 2 Sheets-Sheet 1 1,622,569 March 29 1927' I F. w. BlRTcH METHOD OF AND MEANS FOR HEATING LIQUIDS Patented Mar. 29, 1927.

UNITED l STATES l,t22,569 PATENT OFFICE.

FRED WILBR BIRTCH, OF LA PORTE, INDIANA, ASSIGNOR TO BASTIAN-MORLEY COM- PANY, A CORPORATION OF INDIANA. i

METHOD OF AND MEANS FOR HEATING LIQUIDS.

Application led February 3, 1923. Serial No. 616,867.

My invention relates to the heating of liquids, and has for its general object to provide an improved met-hod o1 and means for imparting to liquid, that is free to circulate through a constantly-open heating passage, a high temperature rise on a single traverse through the heating passage, substantial commencement oi circulation being retarded until the liquid has reached a high temperature.

Circulatory liquid heating installations take many forms for many uses, to which myiinvention is applicable, but one wellknown form is the domestic hot water heater for raising water from its raw temperature to a much higher temperature below boiling point, and by way of example my invention will be described as applied to such a use. Frequently such a system comprises a storage tank having a raw water inlet and a service pipe outlet, said tank having also circulatory piping connections to a heat-absorption element of the system, to which element heat is exteriorly applied. Whether such heat-absorption element takes the form oit a piping coil, a spreader, or other passage of the flow piping; and whether the heat applicator takes the form or" a gas burner, electric appliance, or other source of heat, the functioning of the ordinary installation is the same. To bring any portion of the water contained in such an ordinary system from a low temperature of say 70 degrees up to a relatively high temperature of say 180 degrees, the entire body of the water in the open circulatory system must be heated to a temperature much above the raw lWater temperature. The reason is that in an open or unrestricted circulatory system water-flow through the heat-absorption element, engendered by ei;- pansion of the water therein, begins with a comparatively small rise of temperature and to secure in the ordinary system such a relatively large temperature rise as that above suggested it is therefore necessary to pass the whole body oi water through the heat-absorption element a plurality of times before any of the water attains the high temperature desired.

I believe it to be true that systems have been devised providing valves (either manually controlled ory thermostatically controlled) in the flow piping beyond the outlet of the heat-absorption element, adapted to remain closed until the temperature oi"- the water initially in the heat-absorption element is raised to the temperature ultimately desired, and then by variable adjustment of the valve, adapted to maintain approximately a flow-rate such that heat absorption raises the water continuously passing through the heat-absorption element to the stated temperature; and I believe that systems have also been for steam-generation) wherein the passages oit' the heat-absorption element are so choked or restricted in capacity, in proportion to their surface exposure to the applied heat. that the liquid will flash to the desired temperature or into steam in a single traverse of the heat-absorption element. To the best of my knowledge, however, no method or means has heretofore been devised aitording an open circulatory system-that is to say, an unrestricted, large-passaged valveless organizatiom-in which, nevertheless, the liquid may, in a single traverse of a heat-absorption area, be raised in temperature to a very high degree, representing what I term a highrise from raw liquid temperature to heated liquid temperature. These seemingly-irreconcilable desiderata I attain by a novel method of treating the liquid, and` in an apparatus which may be at once extremely simple, inexpensive, free from complications, facilely regulated or initially constructed to give a desired temperature rise over a considerable range of operations, and susceptible oi' embodiment in varied specific forms to meet many and varied requirements.

In the drawings, wherein I have illustrated a single, simple embodiment of my invention lor purposes of disclosure, a heating system is shown in which the circulatoryA arrangement includes a storage tank for water to be heated to a temperature below boiling point, the heat applicator being of gas-burner type and the heat-absorption ele ment comprising spreaders; but it Will be understood that in its broader aspects my invention is not limited to these selective particulars, and that many changes in construction, arrangement and specific application may be made without departure from the spirit of my invention within the scope of the claims hereto appended.

Inthe drawings Fig. l is a diagrammatic representation of a hot water heating sysdevised (especially tem; Fig. l2 is a vertical section through the heater casing, showing parts in elevation; Fig. 3 is a reduced horizontal section on line 3-3 of Fig. 2; Fig. 4L is a vertical section on line 1 -4 of Fig'. 2; and Figs. 5 Vand 6 are details of a convenient form of spreader.

According to the method that I employ for attaining the desired results heretofore stated, I subject the liquid, in an open circulatory systein,-valveless and substantially `unobstructed--to the application of heat ata plurality (preferably two) of different points or heat-absorption areas, these two areas being so related one to the other that the l-iquid How tendency engendered in the one area, by heat-absorption and consequent expansion oi the liquid, is resisted or opposed and retarded by the effect ci heat supplied to another area; and I supply heat to theliquid in these respective areas in such proportionthat the flow-tendency engendered in one area preponderates over the resisting-tendency ot another Iarea only when the liquid temperature in the dominant area has reached a point relatively high above the raw-liquidtemperature.

Such terms as flow-tendency, resistance, and resistingtendency, I have used herein in 4their broader sense and in some instances in a somewhat figurative sense, but they aptly and tersely express the actions and ftorce tendencies which occur in the system. I appreciate that circulation ot the liquid inthe system ispdue to the fact that the hot liqu'id is lighter than the cooler lliquid and is displaced b-y the latter.

Referring to Fig. 1, 10 indicates a hot water storage ltank to which 'leads the lsupply ,pi-pe 11 from the city mains or other source of supply and lfrom which leads the4 service pipe 12. The tank has connections, for 1location circulation, to a heating structure J1 31in which are the heat applicator 14 andthe sp-readers `15 and 16. In the particular construction shown, a sindle gas burner 14 may Vsupply heat -to boti 4absorptionelements 15 and `16, although if vdesired separate heaters for these t-wo elements may be provided. rI`hese two heat absorption elements are connected I in series, or successively in-the circulation system, in tree communication with the tank 10. Thus the intake pipe 17 runsfrom the bottom of tank 10 to ,thel secondary or retarding heat-absorption-element 16 and the pipe 17 iuns from the` primary or dominant heat-absorption element 15 to the top of the tank, while communication pipe structure 18 connects the two heat-absorption elements to complete the circuit.

The spreaders 15 and v16 may be any suit-- able form, preferably ot good heat-absorption eiiiciency, one suitable construction being shownin detail in Figs. 5 and 6. In

such Vspreaders water may flow through the bottom oriice 19, lower spreading chamber 2O and upper, hollow ribs 21, to the outlet opening 22, all with free, unrestricted passages adequate to the capacity ot the tlowpiping.

The arrangement for insuring difference in heat-absorption in the two spreaders, or areas for the creation of opposed eects, of water-flow tendency in the one area and flowresistance in another, may be provided for in various ways, but it is my preference to make the spreader-s duplicates in size and construction, and to differentiate, asbetween the two, the amount ol heat supplied thereto; this being one eiective manner .of insuring that the water will not be heated as fast in one area as in the other, or, more broadly stated, that there will be a ditl'erence in the rate ot' temperature-increase, or heat-absorption rate, asbetween the two heat-absorption areas. Further, tor varying the specific operation oic the system, and enabling the user to adjust tor a particular temperature rise, variation may be made in the heat-difference aiecting the spreaders. Ars one particular means to this end I have shown the heater 13 as comprising a shell 24 divided into two compartments 25 and 26 for the respective spreaders 15 and 16, the partition 27 having a dampered opening 23. Ot course heat supplied from the gas burner 14 first impinges on the dominant spreader 15 but will, with lessened effectiveness, vpass through 1the opening 28 to the secondary spreader 16 before reaching the flue or stack 29. A heat by-pass flue `3() may open from the lower chamber 25 to the stack, and a damper 31 having openings 32 and 33 may control both the port 23, and the by-pass 'flue 30 to close the former as it opens the latter, and vice versa. Thus the amount oit heat delivered to upper chamber 26 is Variable and nice variable apportionment of heat supply to the two spreaders is attained. 0r the specific operation of the systemmay be varied by regulating the amount of heat liberated by the burners.

Further, it is as one available manner ot insuring that the eil'ect of heating one heatabsorption area ot the circulation system will be to resist the flow tendency engendered in the other, dominant area, that I mount the secondary spreader 16 ata higher elevation than the primary, dominant spreader 15. In the communication pipe structure 18, I provide-a downlcg 35, a U-bend 36 and an extension. piping unit 37 (which-may be eliminated it desired) in the form lof an inverted U the legs ot which slidably enter thestated pipes and 36. The cooler and hence heavier liquid in ythe tank and pipe 17 tends to torce the'heated, and 'hence lighter liquid in the secondary spreader 16 upward and it may be said to be trapped in the upper spreader and the upper portion of the piping 18, but such trapped hot water must flow down the pipe 35`in order to r'each the intake side of the dominant spreader 15.

It will be apparent that by reason or the difference in elevation ofthe spreaders, and the fact that the upper spreader tends only to trap the water heated thereby, rather than to engender a circulation through the whole piping system, the heat-absorption in the lower dominant spreader must materially exceed the heat-absorption in the upper secondary spreader in order that theaction of the primary absorption unit on the downleg shall overcome the resisting or ietarding influence of the secondary heating unit 16, this arrangement in different elevations being one desirable manner of. insuring that liquid flow will begin only when the heatabsorption in the dominant element greatly exceeds the heat-absorption in the secondary element.

In operation the raw water initially in the tank 10 may stand, say, at 70 degrees when the gas burner 141 is lighted. By the apportionment of heat to the two spreaders, (as one effective manner of insuring a difference in heat-absorption by the liquid contents of one absorption structure as against the other in a given length of time) 'it is assured that there will not be enough temperature difference between the water in the secondary spreader 16 and the water in the dominant spreader 15 to overcome the resistance or retarding effect of the Water in the upper spreader and upper portion of the piping 18 until the liquid in spreader 15 has attained a temperature relatively high above the raw-water temperature; say a rise from degrees to 180 degrees, or other rise. Consequently no hot water flows at all through the pipe 17 to the top of the storage tank until the 180 degree temperature, in the above example, is reached and then circulation starts with a rush. Consequently by running the apparatus for a short time one can heat a shallow body of water at the top of the tank 10 to 18() degrees, still treating with the above example, without affecting (further than to a slight incidental extent due to convection and internaly circulation within the tank) the raw water body of 70 degrees temperature therebelow. It will be understood, of? course, that the figures given are illustrative, only. When the temperature of the raw water varies (between summer and Winter, say) adjustment can be inade, as by damper regulation, or variation in heat application, to maintain the desired outflow temperature from the heater.

In Figs. 2 to 4 I have illustrated a construction of larger capacity than could economically be built by mere enlargement of single spreaders as the two respective heat-absorption units, each heat-absorption unit (lfand 16a) in the modified form shown being composed of a plurality of spreader-s arranged in parallel relation,

absorption area having the higher absorp- .1

tion rate.

2. The method of heating liquid in an open circulatory system to result in circulatory flow in response only to a high rise of liquid temperature, which consists in subjecting heat-absorption; areas of the -fiow system, located at different elevations therein and connected in series, to heat application such as to raise the liquid temperature in the area ot' higher level more slowly than the temperature of the liquid is raised in the heat-absorption area. of lower level.

3. The method of initiating liquid flow in an open circulatory system upon a relativehigh rise of temperature, which consists in sujecting to heating conditions that will heat the liquid therein at different rates, a plurality of distinct heat-absorption areas of the circulatory system these areas being so related that heat-absorption by the-'liquid in the area having the less absorption rate causes said liquid to resist flow to the heatabsorption area having the higher absorption rate, and varying the effective supply of heat to said areas to control the temperature rise.

Il. The method of heating liquid in an open circulatory system to result in 'circulatory flow in response only to a relative high rise of liquid temperature, which consists in subjecting heat-absorption areas of the flow system, with the lower one in arrangement to engender circulation and the upper one in arrangement to tend to pocket its heated liquid located at different elevations therein and connected in series, to heat application such as to raise the liquid temperaturc in the area of higher level more slowly than the temperature of the liquid is raised in the heat-absorption area of lower level.

5. In a liquid heating system, the combination of heatabsorption elements arranged in series in an unobstructed circulatory systeni, said elements being arranged to permit heat-engendered circulation of the liquid only Se f lll)

in accordance with preponderating heatabsorption kin one element as compared with the other element, and means `for supplying heat to said elements 1to1' `absorption by the liquid in said elements at different rates.

1G. In a liquid iheatiug system,.the combination of two heat-absorption elements connected in series in a open circulatory system, said elements being at different elevations, with the itop outlet `oi the 4upper element connected by a down leg with the Abottom inlet of the lower element `and means for supplying heat to said `elements suitably for absorption yat different rates, to heat the liquid :of the lower element faster than the liquid of the upper element is heated.

7. 'In a liquid heating system, the combination of two heat-absorption elements conneeted in series in an lopen circulatory system, said elements being at different elevations to provide a hot water trap, and means for supplying selectively apportioned quantities of heat to said elements vsuitably for absorption at different rates, to heat the liquid of the lower element faster than the liquid of the upper element is heated.

f8. In a liquid heating system, the combination of open liquid circulatory lpassa-ges including` two heat absorption areas at different levels, and means for heating said areas simultaneously but to allord a `higher absorption rate for the lower-level area than that aifecting the higher-level area.

l9. The method of initiating fluid 2flow in system of the class described which con sists in heating a plurality of heat-absorption areas so that one retards the .circulatory action ci? the other.

l0. In a fluid heating system, :the combination of two heat-absorption areas in series and heating means Iarranged so that one Varea is heated more than and retards the circulatory action of the other area.

11. The method oit initiating fluid How in an open circulatory system which consists in arranging a plurality of heat-absorption areas at diilferent levels and heating them so that one acts to retard the circulatory action of the other.

12. The method Aof initiating fluid `How in an open circulatory system which consists in arranging a plurality -of heat-absorption areas at `different `levels and heating them so that one acts to-retard the circulatory action ofthe other, and Varying the ettective heating of said areas to control the temperature rise.

i3. In a 'fluid heating system, zthelcombination oil two heat-absorption areas in series and at different levels, heating means arraiiged so that one area is heated more than and retards the circulating action of the other area, and means for varying the effect-ive heating of said areas 'to control ithe temperature rise.

In testimony whereof, I have hereunto subscribed at Chicago, Illinois, this 22nd day of January, 1923.

FREI) IVILBUR fBIRTCH.' 

